In a client/server network, session tracking keeps a server from having to ask whether a client (e.g., user) has connected before each time the server receives a request from the user. This is important in, for example, today's electronic commerce (e-commerce) Web applications.
There are generally two types of Internet communication protocols, i.e., statefull and stateless. A server associates a state with a connection. Statefull protocols, such as Telnet and file transfer protocol (FTP), can process multiple operations before closing a connection. The server generally knows that all requests come from a single user.
Stateless protocols, such as hypertext transfer protocol (HTTP), open separate connections to a server anytime a client requests a web page, and the server doesn't know a context or scope from one connection to the next connection. Each transaction is a single isolated transaction.